It's intentional for Monster 2's that those two fingers goes on same IK point. It's a race feat. It can't move either of those two fingers without moving the other.
The mouth is a tad trickier due to that the upper and lower part of the mouth each has 3 hard/soft bone points, and since we can just rotate the IK points most of the mouth
doesn't follow and gets out of place. Working on that still.
The hardest part with it all is the bone list. Let's say that you have a creature with 200 bones, and you want them all to have IK control points. Then you have
to manually add each of these 200 bones to the creatures line of bones:
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It becomes very tedious and monotone quickly, and if you make a typo you have a long list to go through to find it.
Rigging the meshes is the easy part.
The mouth is a tad trickier due to that the upper and lower part of the mouth each has 3 hard/soft bone points, and since we can just rotate the IK points most of the mouth
doesn't follow and gets out of place. Working on that still.
The hardest part with it all is the bone list. Let's say that you have a creature with 200 bones, and you want them all to have IK control points. Then you have
to manually add each of these 200 bones to the creatures line of bones:
<5555><spine0><spine1><spine2><spine3><spine4><spine5><spine6><spine7><spine8><spine9><spine11><spine12><spine13><spine14><spine15><spine16><spine17><spine18><spine19>[...]
It becomes very tedious and monotone quickly, and if you make a typo you have a long list to go through to find it.
Rigging the meshes is the easy part.